SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb4fb9a708a6669c29319feceae4a33ebbec82bfd870d021f3bde1a0efe69527' 
  AND token = 'c/qfFyPQuRuwksihbZ4o7bxQmtX3jNFMg4t1gIOUxv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}